Validation of a Nonlinear Aluminum Honeycomb Constitutive Model for Impact Analyses

摘要

A new constitutive model for large deformation of aluminum honeycomb has been developed. This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. The honeycomb model has been implemented in the transient dynamic Presto finite element code for dynamic impact simulation. In order to extract useful constitutive-parameter information from crush tests each test configuration and process is simulated with a Presto finite element model to analyze the non-uniform strain/crush behavior within the test samples. Model parameters have been identified to fit uniaxial and biaxial crush test data for high density (38lb/ft3) aluminum honeycomb. Possible sources of experimental and modeling uncertainty are discussed. An energy based validation metric will be presented and applied to enable quantitative comparisons between validation experimental data and model predictions. On-going work in model validation is discussed.